1. Field of the Invention
The present invention relates to novel methods of preparation of packaging bags for bottle by utilizing heat shrinking film, novel methods of preparation of packaging bottles and novel apparatus utilized therefore.
More particularly, the present invention relates to methods of continuous preparation of packaging bags for bottles made of heat shrinking film sheet which is fitted over the top of a bottle having a narrow opening at the top and allowed to heat shrink by heating to make a packaging bottle fitted tightly in the shape of the bottle with the packaging bag by the shrinking force of the bag and an apparatus utilized therefor. The present invention also relates to methods of preparation of packaging bottles which comprise fitting a packaging bag made of heat shrinking film sheet over the top of a bottle having a narrow opening at the top and heat shrinking the packaging bag by heating to make a packaging bottle fitted tightly in the shape of the bottle with the packaging bag by the action of the shrinking force of the bag and an apparatus utilized therefor.
2. Description of the Prior Art
Packaging of bottles by utilizing heat shrinking film has been widely practiced.
Packaging bottles having heat shrinking film can be prepared by fitting a bag made of film formed by closing an end of cylindrical film by heat sealing, such as shown in FIG. 9, over a bottle and then by heat shrinking by heating to make a tightly fitted film over the outside of the bottle in the shape of the bottle.
The closed end of the packaging bag is made into a shape of arch as shown in FIG. 9 to make the packaging film fit tightly in the shape of the cap of the bottle after heat shrinking. If the closed end of the packaging bag has a shape of straight line, the film sheet at the corners of the closed end do not fit tightly to the shape of the cap of the bottle but remain separated from the face of the bottle.
The packaging bag having the closed end of arch shape as shown in FIG. 9 shrinks to the same shape as the bottle. The cap of the bottle is fixed by the shrinking action of the packaging bag and this condition makes so called virgin seal. When the face of the film sheet is printed with marks and labels, the marks and labels are easily placed on the face of the packaging bottle even when printing is not possible on the bare face of the bottle.
Packaging bottles fitted with heat shrinking film are generally prepared by the following method: a number of packaging bags attached with a scrap piece S to each of the bags are prepared by heat sealing the closing end T of the packaging bags in a shape of arch as shown in FIG. 10; after the packaging bags thus prepared are stacked, scrap pieces S are discharged manually; the remaining packaging bags R as shown in FIG. 9 are stored once in a bag supply box of a packaging machine in the form of stacked bags; the packaging bag is taken out one by one to a packaging table and placed over the outside of a bottle; and then the packaging bag is allowed to shrink by heating to prepare a packaging bottle fitted with the bag.
The conventional method described above has problems that efficiency of the operation is low because manual operations are included during the process and also because blocking and letting air out of a bag are not easily made and that the number of deficient packaging, such as misplaced printing and uneven shrinking of the film, is increased because the packaging bag makes erroneous movement from the correct position during shrinking.
The conventional method described above has another problem that automatic continuous fitting of the packaging bag to the bottle cannot be smoothly operated in spite of numerous trials for the purpose. This problem arises because the diameter of the packaging bag cannot be made much larger than the diameter of the bottle to achieve good fitting of the film to the bottle by heat shrinking.